Hand gripping tool

ABSTRACT

A hand tool comprising a core member extending along a longitudinal axis of the tool; at least two jaws moveable relative to the core member so as to be openable and closeable, but constrained in a forward direction substantially parallel with said longitudinal axis, a sleeve member arranged to be moveable substantially parallel with the longitudinal axis relative to the core member, the sleeve member having at least one forward facing jaw-engaging surface.

This application claims priority of International Application No.PCT/GB99/03093, filed Sep. 16, 1999, entitled A HAND GRIPPING TOOL(published in English), which in turn claims priority of Great BritainApplication No. 9821888.6, filed Oct. 7, 1998, and Great BritainApplication No. 9907797.6, filed Apr. 7, 1999.

BACKGROUND OF THE INVENTION

The present invention relates to hand tools for gripping objects and inparticular, although not exclusively, to hand tools for gripping andextracting protruding screws, nails and other semi-permanent mechanicalfastenings from walls and other surfaces, and to hand tools for holdingcommon tools and accessories, such as blades and screw-driver bits.

During the refurbishment of surfaces, such as walls, it may be necessaryor desirable to extract previously installed, now unwanted,semi-permanent mechanical fittings.

Damaged or stubborn mechanical fittings including pins, nails, heavyduty staples, wall plugs, self-tapping screws, studs and other similarobstructions are difficult and potentially dangerous to remove, andoccasionally considerable damage occurs to the surrounding wall.Inappropriate extraction techniques can also lead to personal injury.

Known gripping and extraction tools include mole grips, pliers, pincersand claw hammers. Embodiments of the present invention aim to providehand tools which are more flexible, easier to use, provide a firmer,more secure (and hence safer) grip, enable gripping of a wide range ofshapes and sizes of objects, and enable a greater extraction force to beexerted on objects compared with known gripping and extraction tools.

SUMMARY OF THE INVENTION

According to the present invention there is provided a hand tool forgripping an object, the hand tool comprising a core member extendingalong a longitudinal axis of the tool; at least two jaws, moveablerelative to the core member so as to be openable and closeable, butconstrained in a forward direction substantially parallel with saidlongitudinal axis, at least a portion of each jaw extending from a firstend of the core member generally in said forward direction when the jawsare closed, the respective extending portions each having a respectivegripping surface; and a sleeve member arranged to be moveablesubstantially parallel with the longitudinal axis relative to the coremember, the sleeve member having at least one forward facingjaw-engaging surface, the jaws, when open, each presenting a respectivereverse facing engaging surface to the at least one jaw-engaging surfaceof the sleeve member; the sleeve member being progressively moveable inthe said forward direction to urge the at least one jaw-engaging surfaceof the sleeve member against the reverse facing engaging surfaces of thejaws, constraint of the jaws in the said forward direction causingurging of the sleeve member against the jaws to force the jaws to close.The hand tool further comprising two lever pins (11) arranged to extendgenerally transverse to the longitudinal axis and coaxially fromopposite sides of the hand tool at least when the jaws are closed, eachlever pin extending from and being integral with a respective one of thejaws.

Preferably the sleeve member is generally cylindrical, extends along thelongitudinal axis and is arranged coaxially with the core member suchthat it is movable to radially surround at least a portion of the coremember.

Preferably the core member is generally cylindrical and comprises anexternal screw thread, and the sleeve member comprises a correspondinglythreaded bore extending along the longitudinal axis and arranged toreceive and threadably engage the core member such that movement of thesleeve member along the longitudinal axis relative to the core member iseffected by rotation of the sleeve member with respect to the coremember about the longitudinal axis.

Preferably the screw thread is left-handed. This is particularlyadvantageous when the hand tool is used for gripping and removingright-hand threaded objects from the surfaces in which they areembedded. The left-hand thread of the core member and sleeve memberensures that the hand tool's grip is not loosened when it is used torotate the embedded object in the anti-clockwise direction in an attemptto remove it from the surface. The grip may, as a result of theleft-handed thread, tighten as the object resists rotation.

The sleeve member may be generally cylindrical, and may comprise anouter surface adapted to be engaged by a spanner or socket for applyingtorque to the sleeve member about the longitudinal axis. Thus, a greatergripping force may be applied to the object. The adaptation to thesleeve member may take the form of a pair of diametrically opposedflats, or for example, an axially extending section of the sleeve membermay have a generally hexagonal outer cross-section.

Advantageously, the sleeve member may comprise a handle portion adaptedto facilitate gripping and rotation of the sleeve member by hand. Thehandle portion may, for example, take the form of a generallycylindrical portion of increased diameter to enable sufficient torque tobe applied to the sleeve member by hand to achieve sufficient grip onthe object.

Preferably, the sleeve member is not arranged to fully enclose the coremember. Preferably a second end of the core member is arranged to extendthrough the sleeve member in the reverse direction beyond a first end ofthe sleeve member when the sleeve member is in contact with the jaws.

The protruding second end of the core member may be adapted to beengaged by a spanner or socket (for example it may be hexagonal incross-section) and in addition, or alternatively, may be adapted toreceive and be engaged by a socket drive. This adaption may take theform of a suitably dimensioned square cross-section orifice extendinginto the second end of the core member generally along the longitudinalaxis.

Thus, substantial relative torque may be applied between the core memberand sleeve member to close and lock the jaws onto an object, by use ofstandard hand tools engaging with suitably adapted surfaces of the handtool.

Advantageously, the jaws, when forced closed by the sleeve member, areeach arranged to extend beyond a second end of the sleeve member in theforward direction. This is particularly advantageous as the sleevemember does not then obscure the hand tool operator's view of the objectto be gripped, and enables the operator to hold and manually close thejaw members on the object before tightening the grip by urging thejaw-engaging surface or surfaces of the sleeve member into contact withthe corresponding engaging surfaces of the jaws.

The tool may comprise just two jaws.

Preferably, the gripping surfaces of the jaws are arranged to closegenerally radially and symmetrically on the longitudinal axis when thejaws are forced to close by the sleeve member.

Thus, the jaws may be adapted to open and expand radially to receivebetween their gripping surfaces an object inserted generally along thelongitudinal axis.

The jaws may be coupled to the core member, forming a generallyrotationally symmetrical arrangement around the longitudinal axis.

The jaws may be arranged such that when no object is inserted betweentheir gripping surfaces, the jaws may be closed to bring their grippingsurfaces into contact with each other generally on the longitudinalaxis.

Preferably, the gripping surfaces of the jaws are adapted to provide agood grip on a wide range of shapes and sizes of objects. For example,each gripping surface may include a respective flat portion arranged tooppose the corresponding flat portion or portions on the or each otherjaw, respective teeth arranged to intermesh with corresponding teeth onthe or each other jaw, and/or respective teeth arranged to oppose butnot intermesh with corresponding teeth on the or each other jaw.

Each gripping surface may in addition, or alternatively, comprise agenerally V-shaped groove arranged to extend generally along thelongitudinal axis to facilitate gripping of generally cylindricalobjects aligned with the longitudinal axis.

Preferably, the or each forward facing jaw-engaging surface of thesleeve member is inclined to face the longitudinal axis such thatcontact with the corresponding engaging surfaces of the jaws applies aforce to the jaws having a component transverse to the longitudinal axis(i.e. a radial component).

Preferably, the sleeve member has a single forward facing jaw-engagingsurface which is generally frustoconical and is radially disposedsymmetrically about the longitudinal axis.

Preferably, the hand tool has a rotational axis of symmetry co-linearwith the longitudinal axis.

Preferably, the jaws are pivotally coupled to the core member, althoughother coupling arrangements are possible.

Preferably, each jaw comprises a respective pivot pin extending from aside of the jaw, each pivot pin being received in a correspondingrespective slot in the core member, each said slot extending in a planesubstantially perpendicular to the longitudinal axis, the jaws and coremember being adapted to permit rotation of each jaw about its respectivepivot pin in a plane substantially parallel to the longitudinal axis andto permit movement of each pivot pin, in its respective slot, transverseto the longitudinal axis. Thus, the jaws may hinge open but are alsopermitted a degree of purely translational motion relative to the core,namely a translation in a direction transverse to the longitudinal axis.

Advantageously, each jaw may comprise two of the said respective pivotpins, the two pivot pins of each jaw extending coaxially from opposingsides of the jaw, and the core member may comprise at least one furtherslot, the or each further slot extending in a plane including orparallel to the longitudinal axis and hence perpendicular to the planeof the slots receiving the two pivot pins of a respective one of thejaws, the or each further slot being arranged to accommodate a portionof a respective one of the jaws to permit rotation of the jaw about itspivot pins.

Preferably, the further slot or slots are arranged to engage sidesurfaces of the accommodated portions of the jaws to contain rotation ofthe jaws about the longitudinal axis relative to the core. Thus, torqueabout the longitudinal axis may be transmitted to the jaws by means ofthe core member.

Advantageously, the hand tool may have two jaws, the respective slots,pivot pins, jaws and core member being arranged to permit parallelseparation of the gripping surfaces.

This feature enables the jaws to provide a firm and extended grip ongenerally cylindrical objects.

Advantageously, the pivot pins may be constrained in their respectiveslots by the sleeve member at least when the jaws are closed, and thesleeve may be movable in the reverse direction sufficiently to releasethe pivot pins from their respective slots to enable decoupling of thejaws from the core, and hence enable removal and replacement of jawsfrom the tool.

Thus, the jaws may be replaceable, and different jaws may be utilised(i.e. coupled to the core member) according to the nature of the objectto be gripped and/or extracted.

Advantageously, for each jaw, the respective reverse facing engagingsurface is generally inclined at an angle to the respective grippingsurface, the angle of inclination being generally the same as thatbetween the jaw-engaging surface or surfaces of the sleeve member andthe longitudinal axis.

This feature, when coupled with transverse movement of the jaw pivotpins in their slots with respect to the longitudinal axis, enables arelatively large contact area to be maintained between the sleeve memberand each jaw for a range of jaw separations. The rear facing engagingportions of the jaws are thus inclined at the same angle as thejaw-engaging surface of the sleeve member to the longitudinal axisprovided that the gripping surfaces are parallel to the longitudinalaxis.

Although the jaws may be arranged to present respective reverse facingengaging surfaces to the sleeve only when the jaws are open, it ispreferable that these engaging surfaces are presented to thejaw-engaging surfaces of the sleeve even when the jaws are closed toenable tightening of the jaws onto even very small objects.

This may be achieved by employing jaws which taper sufficiently outward(i.e. transverse to the longitudinal axis) in the forward direction fromthe core member.

Preferably, the hand tool comprises at least one spring arranged to biasthe jaws open.

Advantageously, the hand tool may further comprise two lever pinsarranged to extend generally radially (transverse to the longitudinalaxis) and coaxially from opposite sides of the hand tool, at least whenthe jaws are closed.

The pins may be used to facilitate the manual application of torque tothe sleeve member or core member to close or release the jaws, or may beengaged by a lever pivoting on a fulcrum to pull the hand tool from asurface.

Preferably, each lever pin extends from and is integral with arespective one of the jaws such that when the lever pins are used topull the hand tool (for example to extract a gripped object from awall), the grip is not loosened, as might be the case if the pins werelocated on the sleeve member.

Preferably, the hand tool may be combined with a lever assemblycomprising a lever having a first end adapted to engage the lever pinsof the hand tool, a second end providing a handle, and fulcrum pinsextending transversely and coaxially from a region between the first andsecond ends, a plate member for positioning against a surface from whichan object is to be extracted, and a fulcrum pin support member extendingin a direction generally perpendicular to the plate member and providinga support for the fulcrum pins.

The fulcrum pin support member may, advantageously, be adapted toprovide an adjustable height support for the fulcrum pin relative to theplate member.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an isometric view of an extraction tool embodying thepresent invention, with jaws closed;

FIG. 2 shows an isometric view of the extraction tool of FIG. 1, withjaws open;

FIG. 3 shows a perspective view of the extraction tool of FIGS. 1 and 2in combination, with extraction lever and integral plate;

FIG. 4 shows a side view of the extraction tool of FIG. 1;

FIG. 5 shows a plan view of the extraction tool of FIG. 1;

FIG. 6 shows a rear view of the extraction tool of FIG. 1;

FIG. 7 shows a front view of the extraction tool of FIG. 1;

FIGS. 8(a)-(d) show plan, side, rear and front views respectively, ofone of the jaws of the extraction tool of FIG. 1;

FIG. 9 shows an isometric illustration of the jaw of FIGS. 8(a)-(d);

FIG. 10 shows a part-section of the orthographic plan view of theextraction tool of FIG. 1;

FIG. 11 shows a cutaway isometric view of the sleeve of the extractiontool of FIG. 1;

FIG. 12 shows a schematic cutaway isometric view of the extraction toolof FIG. 1; and

FIG. 13 is a schematic diagram of a hand tool embodying the presentinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to FIG. 13, this Figure is a highly schematic diagram of ahand tool embodying the present invention, and is intended to illustratesome of the essential and optional features of the present invention.The hand tool of this example comprises a generally cylindrical coremember 4 extending along a nominal longitudinal axis L and having afirst end 401, facing a nominal forward direction, and a second end 402,nominally facing reverse.

Two jaws are arranged at the first end 401 of the core and are coupledto the core member 4 by means of pins 13 received in slots 14 in thecore, the slots extending in a plane generally perpendicular to thelongitudinal axis L.

The coupling between the jaws 2 and the core 4 allows the jaws to openand close but constrains their movements in the forward and reversedirections, generally parallel to the longitudinal axis.

A portion of each jaw extends from its pivot pin 13 beyond the first end401 of the core and includes a respective gripping surface 200.

A generally cylindrical hollow sleeve member 1 partly surrounds the coremember and extends generally coaxially with the core member along thelongitudinal axis. In the Figure, the sleeve is shown in cross-section.An inner bore of the sleeve comprises a screw-thread 101 that engages acorresponding external thread 41 on the core member. Relative rotationof the core 4 and sleeve 1 about the longitudinal axis L causes relativeaxial movement between these two members.

By appropriate relative rotation with respect to the core member, thesleeve member 1 is progressively movable in the forward direction tobring a forward facing jaw-engaging frustoconical surface 102 intocontact with the corresponding rear facing engaging surfaces 202 of thejaws. Further forward movement of the sleeve forces the jaws to close asa result of their coupling to the core member. The rear facing engagingsurfaces of the jaws 202 are inclined at an angle θ to the grippingsurface 200. The jaw-engaging surface 102 of the sleeve 1 is alsoinclined at the angle θ to the longitudinal axis L. Thus, when thegripping surfaces are substantially parallel to the longitudinal axis,the total contact area between the sleeve member and jaws is a maximum.

The jaws are able to rotate about their pivot pins (see the arrow R) ina plane including the longitudinal axis L. However, the pivot pins arealso able to slide transverse to the longitudinal axis in their slots 14(in the general direction shown by the arrow T). This sliding movementenables the jaws to open and close to a degree with their grippingsurfaces 200 parallel, and so facilitates secure gripping of objectsextending along the longitudinal axis.

The combination of rotational movement about the pivot points, and thesliding of the pivot axes transverse to the longitudinal axis enablesthe tool to provide a secure grip on a wide variety of shapes and sizesof objects.

The common angle of inclination between the engaging surfaces 202 of thejaws and their gripping surfaces 200, and between the jaw-engagingsleeve surface 102 and the longitudinal axis L enables the maximumcontact area between sleeves and jaws to be maintained whilst closingthe jaws gripping surfaces in parallel.

In this example the jaws 2 are arranged to extend beyond the forward end103 of the sleeve 1 even when fully closed, so that the user's view ofthe object to be gripped is not fully obscured by the sleeve 1. Thisarrangement also enables the jaws to be held closed by hand on theobject while the sleeve is rotated to bring it forward and lock the jawsonto the object.

Furthermore, in this example, the sleeve is fully separable from thecore by unscrewing in the reverse direction. For a range of forwardpositions, the sleeve member constrains the pivot pins 13 in their slots14, but once the sleeve is moved sufficiently far in a rearwarddirection, the pins can be removed from their slots and the jaws can befully decoupled from the rest of the tool. Thus, the jaws areremovable/interchangeable and different shaped jaws can be inserted,depending on the intended use of the tool.

The sleeve member and core member are further arranged such that whenthe sleeve is positioned to close the jaws, the second end 402 of thecore 4 protrudes through the sleeve, beyond its reverse facing end 104.

An axially extending section 403 of the core at the second end 402 ishexagonal in cross-section to enable torque to be applied to the coremember by means of a spanner or socket.

FIG. 1 shows a perspective view of a further hand tool embodying thepresent invention. The principle of operation of this embodiment isgenerally the same as that of the example shown in FIG. 13. In theexample of FIG. 1, the sleeve member 1 is adapted to provide a handleportion 110 of increased diameter to facilitate gripping and rotation ofthe sleeve. A forward portion of the sleeve member takes the form of ahexagonal nut 111 and a forward facing jaw-engaging frustoconicalsurface 102 is provided by an inner surface of this nut portion 111. Theflat sides of the nut portion 111 may be engaged by the driving surfacesof a spanner to enable increased torque to be applied to the sleevemember.

The embodiment of FIG. 1 includes just two jaws 2, 3. In this Figure thejaws are shown closed, with their rear facing sleeve engaging surfaces 7(i.e. 202) in contact with the jaw-engaging surface 102 of the sleevemember.

Each jaw member 2, 3 comprises a pin 11 which extends generallytransverse to the longitudinal axis when the jaws are closed. These pins11 facilitate manual holding of the jaws and core member 4 as the sleevemember is rotated relative to them, and further enable a suitablyadapted lever to be inserted underneath the pins to lever the tool awayfrom a surface, and so facilitate extraction. By locating these pins 11on the jaws 2, 3, the gripping force applied to the object is notloosened as the hand tool is pulled in the nominal reverse direction.

As can be seen from the Figure, the gripping surfaces of the jawscomprise different regions, to facilitate gripping of a wide variety ofshapes and sizes of objects. At the forward-most end of the jaws thegripping surface comprises a flat 8. At an intermediate position thejaws include intermeshing teeth 9, and at a more rearward position thejaws include teeth which oppose each other, meet at points, but do notintermesh. These opposing teeth provide cavities between the jaws evenwhen they are fully closed together.

Referring now to FIG. 2, this Figure shows the embodiment of FIG. 1again in perspective view, but this time with the jaws open. The sleevemember 1 has been unscrewed relative to the core member and has moved inthe reverse direction, such that the jaw-engaging surface 102 no longerforces the jaws closed. With the jaws open, a further feature of thegripping surfaces can be seen. A V-shaped groove 12 is provided on eachgripping surface, extending along the length of each jaw such that itruns, in use, generally along the longitudinal axis. In this example,the depth of the groove 12 varies along the length of the jaws. The Vgroove enables the jaws to grip objects extending along the longitudinalaxis, such as screws and nails more securely.

FIG. 3 shows the hand tool of FIGS. 1 and 2 in combination with a leverassembly which enables a greater extraction force to be applied to anobject partially embedded in a surface.

The lever assembly shown in FIG. 3 comprises a lever 904 having a firstend adapted to engage the lever pins 11 of the hand tool. This first endof the lever 904 comprises two prongs 906 arranged to pass under thelever pins and on either side of the hand tool. The prongs each includea scalloped surface 907 to engage the lever pins of the hand tool at anumber of selectable positions along the prongs lengths.

The lever 904 includes a second end providing a handle 905, and twofulcrum pins 902 extending coaxially from either side of the lever atthe base of the prongs.

The lever assembly 900 further comprises a plate member 901 forpositioning against a surface from which an object is to be extracted.Fulcrum pin support members 903 are pivotally coupled to the platemember 901 and are each rotatable in the direction generally shown bythe arrow B in FIG. 3 to extend in a direction generally perpendicularto the nominal surface engaging front face of the plate member 901. Eachfulcrum pin support member includes a plurality of fulcrum pin engagingrecesses 908, each providing positive location for the fulcrum pins at arespective distance from the surface engaged by the front face of theplace member 901. Thus, the fulcrum pin support members provide foradjustment of the “height” of the lever's fulcrum above the surface fromwhich the object is to be extracted. The lever can be fully disengagedfrom the fulcrum pin support members when not in use, and also thesupport members 903 may be folded flat against the plate member 901 forease of storage and transportation.

The scalloped prongs 906 of the lever 904 enable the separation betweenthe axis of the lever pins and the axis of the fulcrum pins to beadjusted so that, in turn, the mechanical advantage afforded by thelever in applying an extraction force in the direction D to the handtool can be varied. By moving the fulcrum pins 902 into recesses 908progressively further from the plate member 901, the lever assembly canbe used to apply a large extraction force to an object as it isprogressively pulled from a surface.

In FIG. 3, the generally hexagonal end 403 of the core member can beclearly seen protruding from the rear facing end of the sleeve member.Also, the Figure clearly shows a square cross-section recess 404extending into the core member in the forward direction. This recess 404is dimensioned to receive the square driving pin of a socket ratchet.

FIG. 4 shows a side view of the hand tool of FIG. 1. The hexagonallyprofile, axially extending front portion 111 of the sleeve member 1 mayalso be termed a “collar portion” or “nut portion”.

FIG. 5 shows a plan view of the hand tool of FIG. 1 and FIGS. 6 and 7show rear and front views respectively.

FIGS. 8(a)-8(d) show plan, side, rear and front views respectively ofthe right jaw 3 of the hand tool of FIG. 1. In these Figures, thedifferent regions 8, 9 and 10 of the gripping surface can be clearlyseen. Region 8 is substantially flat, region 9 comprises teeth arrangedto intermesh with teeth on the opposing jaw, and region 10 includesteeth arranged to oppose but not intermesh with corresponding teeth onthe opposing jaw, thereby leaving cavities between these teeth. Asurface 300 of the jaw is profiled to maintain clearance around thebull-nose 4000 at the forward end of the core member as the jaw rotatesabout its pivot pins 13. The jaw 3 includes two pivot pins 13 protrudingcoaxially from opposing sides 301, 302 of the jaw. The opposing sides301 and 302 are substantially parallel and are engaged by the innersurface of the main transverse slot M running through the bull-nosed endof the core member. In FIG. 10, for example, the main transverse slotextends in the plane of the page.

Returning to FIG. 8, the axis of the pins 13, about which the jawpivots, is parallel to the general plane of the gripping surface andperpendicular to the axis along which the lever pin 11 extends. The rearfacing sleeve-engaging surface 202 of the jaw is inclined at an angle θto the general plane of the gripping surface. The right jaw 3 of thegripping tool is shown in perspective view in FIG. 9.

In FIG. 10, which is a plan view of the gripping tool, the bull profilednose 4000 of the core member 4 can be clearly seen, cleared by theprofiled surface 300 of the jaws. The sleeve member 1 is shown incross-section, and it can be seen that the sleeve member is fabricatedfrom a number of components. One component includes the handle portion110, and another the hexagonally profiled collar, together with thethreaded inner surface (i.e. bore). In this Figure, details of thethread on the core member and sleeve member are not shown.

FIG. 11 shows a cut-away perspective view of one component of the sleevemember shown in FIG. 10. The inner screw threaded surface 101 of thecomponent can be seen, along with the frustoconical jaw-driving surface102 and collar portion 111.

FIG. 12(a) shows a schematic cut-away illustration of the hand tool ofFIG. 1, showing the threaded outer surface of 41 of the core member 4.

FIG. 12(b) is a schematic perspective view of the forward end of thecore member of the embodiment shown in FIGS. 1-11, illustrating therelative positioning of the main and pivot receiving slots with respectto the longitudinal axis L. The main transverse slot M extends in aplane including the longitudinal axis and at right angles to the pivotpin receiving slots 14. The pivot receiving slots 14 and the main slot Mintersect. Side surfaces M2 of the main transverse slot M engage sidesurfaces 301, 302 of the jaws, enabling torque to be transmitted fromthe core member to the jaws about the longitudinal axis L. In the highlyschematic FIG. 12(b), the ends of the core member are shown generallysquare. In preferred embodiments of the present invention, however, theend is profiled, as shown by the broken line D.

When the pivot pins of the jaws are located in their respective slots14, forward movement of the jaw along the longitudinal axis isconstrained by the T-bar members T1 and T2.

Features of the embodiment shown in FIGS. 1-12 are as follows:

Part 1: sleeve member incorporating handle; Part 2: left jaw; Part 3:right jaw; Part 4: core; Part 5: spring for jaws; Part 6: lever andintegral plate (also referred to as part 900); Feature 7: linear cams(engaging surfaces 202); Feature 8: flat portion jaw grip; Feature 9:crocodile teeth, crinkle and grasping jaw; Feature 10: widening serratedcavity jaw to accommodate form of foreign object (e.g. screw heads)Feature 11: external jaw fulcrum (lever) pins; Feature 12: longitudinaltapering “V”; Feature 13: jaws hinge (pivot) pins; Feature 14: slots inT bar of the products core; Feature 15: ¼ inch drive; Feature 16: 20 mmhexagonal feature; Feature 17: 38 mm nut portion of sleeve member;Feature 18: pressure plate stand-off (also known as fulcrum pin supportmember); Feature 19: forks lever trunnion (also known as lever fulcrumpins 902); Feature 20: scalloped location point (907).

As shown in FIG. 2, the internal jaw design reduces the chance of theextraction tool slipping and twisting off the mechanical fastening whenin use. This is due to the combined features which constitute theinternal surfaces of the jaw, longitudinal tapering “V” feature 12 andchanging profile of the jaws 8, 9, 10; the latter illustrated in FIG. 9.

FIGS. 8 and 9 shows the flat pinching shape of the jaw feature 8 whichminimises the risk of cutting the foreign objects in two. Themid-section of the jaw has grasping, interlocking teeth feature 9. Thesymmetrical shape of the jaws teeth feature 10 accommodates the largerfastening and screw heads.

FIG. 10 illustrates how the jaw is designed to close in two planes toimprove flexibility and ensure adequate location; the jaws close in apincer movement and also in parallel motion. This is possible becausethe jaws hinge pins 13 rotate and slide horizontally within the slots 14of the generally T-bar shaped end of the products core 4.

The addition of a spring Part 5 makes the jaws self-opening.

The jaws 2 and 3 are designed with easy removal in mind; this allowsfast, efficient disassembly-assembly, without the use of tools oraccessories, for maintenance, cleaning or jaw replacement.

It is envisaged that jaw replacement would allow greater flexibility andenhance performance. Hardened steel serrated jaws 2 and 3 areillustrated in the drawings, but aluminium soft jaws to minimise damageto objects or very soft nylon/rubber jaws for delicate holdingoperations are conceivable. So too are jaws designed to grasp hexagonalnuts and hex. screw driver bit accessories, a variety of punches,bradawls and centre punches, as well as common knife blades and piercingsaws.

It is envisaged that the extraction tool will be initially tightened onthe mechanical fastening by hand. The handle 1 is turned in thedirection illustrated by arrow A in FIG. 1 while the jaws 2 and 3 areheld. A greater closing force can then be applied by the use of standardtools. (A socket set can fit into the back of the unit as a ¼ inch drivefeature 404 (15), or a 20 mm socket/spanner can be used on the hexagonalfeature 17 of the core 4. The rotating handle 1 has a nut portion toaccommodate a 38 mm spanner).

In some situations the improved grip of the jaws and the torque of thehandle will provide enough of a mechanical advantage to unscrew, loosenand extract objects. More stubborn objects can be tackled with theprovision of the extraction lever 904 and its integral pressure platepart 6 (901). (See FIG. 3) The lever's fulcrum height in the mechanismis fully adjustable to allow the extraction tools jaws to reach within asurface or operate away from the surface. The stand-offs 18 fold up foroperation arrow B, until they stand flat on the plate (901). Slots inthe stand-off allow rapid height adjustment, they are also inclined togive the fork's lever trunnions 19 (902) positive location duringoperation. The fork's lever trunnions rest in an “over centre” positionin the stand-off and this prevents the mechanism from collapsing inoperation. Pressing the lever (905), arrow C, causes a near linearextraction force, arrow D to be applied. The forked lever has aselection of scalloped location points 20 which allow either a highmechanical advantage near the fulcrum or a high velocity ratio at itsend. When not in use the unit folds flat. All pins are in fixed singleshear.

The pressure plate is designed to protect and minimise damage to thesurrounding wall. The lever and plate provide a much greater mechanicaladvantage for linear extraction.

It will be apparent that the above-described hand tool provides a new,safer method of efficiently extracting mechanical fittings. The toolcombines the:

pinching grip of pliers,

purpose designed serration and parallel jaw movement of a vice, toachieve secure grip on the object,

a hands-free, self-locking action,

the ability to apply torque to the gripped object maximised by optionaluse of common tools,

a simple hand operation, and

the flexibility to increase mechanical advantage and so aid extractionby the optional use of a lever engaging the hand tool.

The product described above is designed to be a “locking” extractiontool, which means that once located and tightened it stays attached tothe mechanical fastening concerned.

The jaw design resists slipping and twisting off the mechanicalfastening when in use.

The shape of the jaw accommodates the larger fastening and screw heads.

The shape of the jaw minimises the risk of cutting the object in two.

The jaw is designed to close in two planes to improve flexibility andadequate location; the jaws close in a pincer movement and also inparallel motion.

The addition of a spring makes the jaws self-opening.

In addition the jaws are designed with easy removal in mind; this allowsfast, efficient disassembly, without the use of tools or accessories,for maintenance, cleaning or jaw replacement.

Jaw replacement allows the use of hardened steel serrated jaws,aluminium soft jaws to minimise damage to objects, or very soft rubberjaws for delicate holding operations.

The extraction tool may be initially tightened on the mechanicalfastening (i.e. object to be gripped) by hand. A greater closing forcecan then be applied by the use of standard tools. (A socket set fitsinto the back of the unit as a ¼ inch drive or 20 mm socket/spanner andthe rotating handle has a nut to accommodate a 38 mm open spanner).

In some situations the improved grip of the jaws and the torque of thehandle will provide enough of a mechanical advantage to unscrew, loosenand extract objects. More stubborn objects can be tackled with theprovision of the extraction lever with its integral pressure plate.

The pressure plate is designed to protect and minimise damage to thesurrounding wall. The lever and plate provide a much greater mechanicaladvantage for linear extraction.

Although the above tool has been described with reference to theextraction of objects for surfaces such as walls, it will be apparentthat hand tools embodying the present invention may be used in a widevariety of applications, and different interchangeable jaws may beselected to suit the application.

The extraction tool of FIG. 1 comprises a pair of “plier” jaws whichclose as the extraction tool's “screwdriver” handle is rotated.

The mechanical actuation of the tool's jaws is made possible through theuse of an internal screw thread and the integral internal taper whichacts on linear cams arranged in the design of the jaws.

The mechanical advantage of the unit can be enhanced through the use ofcommon tools being brought to bear on its external surfaces.

The jaws remain locked in the closed position until the extractiontool's mechanism is released by unscrewing the handle and releasing theforce acting on the linear cams arranged in the design of the jaws.

The jaws have a flat pinching end, leading to a cross meshing, bitingjaw and then ending with symmetrically locating serrations which provideadequate cavities to encapsulate mechanical features of a foreignobject.

The jaws articulate on pivot pins from a variable slot allowing parallelclosing and pinching grip.

A purpose designed lever and integral surface pressure plate can be usedin conjunction with the extraction tool's jaw fulcrum pins.

The described jaws can be removed and/or exchanged from the slottedcentral core without the need for the units disassembly or auxiliarytools.

Thus, a multi-purpose holding and extraction tool embodying the presentinvention comprises A: of a pair of shaped jaws.

The overall shape is that of pinching long nose pliers, the face of eachopposing jaw has a combination of internal gripping surfaces to satisfydifferent tasks, the front nipping face is essentially flat, mid-pointthere are intermeshing gripping teeth and at the rear geometricallyopposed serrations for additional grasping. Longitudinally each faceincorporates a V-shaped channel cut from front to back, to the rear onthe jaws it is deeper, this creates point contact for the teeth andallows round and hexagonal components to be encapsulated by the jaws.The V slot is cut at an angle of 120 degrees which provides adequatecavities to encapsulate mechanical features of foreign objects likehexagonal nuts and bolt leads across their corners.

Behind the long nose of the jaws are the trunnion pins which areperpendicular to the jaws and allow a fixture for the tool to be leveredaway from a surface using an appropriate double pronged lever.

In addition the rounded trunnion pins permit the user to prevent thejaws from rotating while the tool handle is being rotated, necessaryduring tightening and releasing of the jaws.

The external side/rear of the jaws are arranged as linear cams. They aretapered to the rear and are rounded axially so as to rotate and fitwithin the revolving collar of the tool's handle.

The rear of the jaws have two flattened top and lower planes so shapedto allow the jaws to fit inside the main horizontal slot, formed in theinner core 4. The jaws forward profile remain proud to compliment thebull-nose of the inner core. The arrangement ensures that the jawscannot twist out of their opposed alignment, but they can revolve andslide independently in the desired horizontal plane. The slot fitensures that torque can be transferred to the jaws through the innercore if required.

To prevent the jaws from pulling out of the horizontal slot, each jawhas vertical coaxial pins which locate into the vertical slots of thetop and lower “T” bars on the threaded inner core. These rigid fulcrumpins allow each jaw to pivot independently opening like a beak or/andthe jaws can slide transversely allowing the jaws to expand parallelwith each other in the horizontal plane. The latter ensuring thatmechanical fastenings like studs can be held along their length.

As the extraction tool's handle is rotated along the screw thread of theinner core, its tapered collar covers the jaws fulcrum pins preventingthem from leaving the inner core.

As it engages the linear cams of the jaws, the result is that the jawsclose, compressing the return spring and tightening the jaws.

Reversing the action, by rotating the handle and collar back along theinner core releases the pressure on the jaws tapers and the jaws areurged apart by the jaw return spring. This is the only way to releasethe jaws.

B: An inner threaded core extending axially through the handle which isengaged threadably with the external handle.

The inner core incorporates a front bull-nosed end to allow the jaws topivot as a beak without corner interference.

It incorporates a wide horizontal slot into which the jaws slide fromopposing sides, the fulcrum pins of the jaws locate into the smaller Tslots. The main slot ensures that the jaws can slide open but cannottwist out of opposing alignment. Further it allows the tool to transfertorque to the jaws if it is required.

The smaller T slots hold the jaws fulcrum pins and prevent the jaws frombeing pulled out of the cores main slot. They ensure that the jaws canpivot and expand transversely as the tool's handle is retracted alongthe threaded inner core.

The inner core is threaded to allow the handle to advance or retract,the internal tapered collar at the front of the handle interacts withthe linear cams of the jaws closing or releasing them. The thread allowsa high mechanical advantage in the mechanism.

The inner core extends from the rear of the handle which allowsancillary tools to apply a rotational torque through the jaws or againstthe external handle when tightening or releasing the jaws.

C: A spring which fits inside the inner core and urges the opposing jawsapart. The spring acts close to the jaw fulcrum pins and it moves themapart transversely.

D: The handle is hollow and is partially threaded so it can advance andretract along the inner core. It can be removed for maintenance byunscrewing it from the rear of the inner core.

In the partially retracted position it exposes the horizontal slot and Tbar forming of the inner core which allows removal of the jaws,necessary for maintenance, or jaw replacement.

At the front the handle incorporates an internal taper, which isparallel with the jaws as the handle advances it overcomes the bias ofthe jaw's springs and closes the jaws, if turned in the oppositedirection the jaws open.

The handle incorporates a hexagonal profile to facilitate the optionaluse of spanners to aid tightening or release.

The handle has an ergonomic profile which makes it comfortable to holdwhile tightening or releasing.

The handle is open at the rear to allow the inner cores external hexconfiguration or internal square drive to protrude and be utilised byrotatable driving tools.

A purpose designed lever and integral surface pressure plate can be usedin conjunction with the extraction tool's jaw fulcrum pins.

While certain novel features of this invention have been shown anddescribed it will be understood that various omissions, substitutionsand changes in the forms and details of the device illustrated and inits operations can be made by those skilled in the art without departingfrom the scope of the claims.

It will be further apparent that features of the present inventiondescribed in the specification (which term includes the claims) may beincorporated in embodiments of the present invention independently ofother described features.

The extraction tool described above is a product which mechanicallygrips and locks onto partially exposed surface mounted, foreign objects,like semi-permanent mechanical fastening. The extraction tool uses arotating handle 1 (arrow “A”), to apply a closing force across twoserrated jaws 2 and 3, using external linear cams 7. The shape of jawserrations 8, 9, 10 fulcrum pins 11 and varied articulation of the jawsare important to achieve optimum location and grip. The jaws externalfulcrum lever pins 11, ensure that an efficient extraction force can beapplied at the strongest and most appropriate point on the product withan optional lever and integral pressure plate 6; the latter protects thesurface from unnecessarily breaking up during use.

The extraction tool could alternatively be used for mechanicallygripping and locking onto accessories.

Thus, embodiments of the present invention relate to a tool suitable formechanically gripping and locking onto objects such as accessories.Alternatively, they can be attached to partially exposed, surfacemounted, foreign objects, like semi-permanent mechanical fastening.

It is therefore an aim of embodiments of the present invention toprovide a tool which is able, efficiently and rapidly, to grip, or gripand extract fittings without causing significant damage to surfaces.

An extraction tool embodying the present invention comprises a rotatinghandle 1 (Arrow “A”) and internal taper to apply a closing force acrossexternal linear cams 7 set in the sides of two serrated jaws 2 and 3.The opposing jaws are urged apart by a wound coil two arm spring, thespring being housed behind the horizontal slot of the threaded innercore. Each arm independently urging one half of the jaw's fulcrum pinsoutwards from the centre along the slots provided in the upper and lowerT bars of the inner central core. The jaws are positioned in opposedalignment and prevented from twisting as they are held horizontal andarticulate/slide from within the horizontal slotted bull-nosed threadedinner core. The jaws fixed fulcrum pins, hinge and slide transverselywithin transverse slots in the upper and lower T bars on the bull-nosedinner core, these offer a varied articulation of the jaws to optimiseopportunities for locating and holding artefacts. This capability isenhanced by the shape of the opposing internal gripping portions of thejaw 8, 9, 10 and the longitudinal deepening V-shaped channel whichcombine to achieve optimum location encapsulation of fittings andsatisfactory grip. The jaws external trunnion pins 11, ensure that theuser can prevent the jaws from rotating as the handle advances along thethreaded inner core, the handles internal taper acts on the jaws linearcams and closes the jaws, reversing direction of the handle andretracting it allows the jaws urged by their spring to open. Thetrunnion pins also offer an efficient extraction point for a two prongedlever force to be applied at the strongest and most appropriate point onthe product. This is achieved by the optional use of a lever andintegral pressure plate 6, the latter protects the surface fromunnecessarily breaking up during use.

What is claimed is:
 1. A hand tool for gripping an object, the hand toolcomprising: a core member extending along a longitudinal axis of thetool; at least two jaws, moveable relative to the core member so as tobe openable and closeable, but constrained in a forward directionsubstantially parallel with said longitudinal axis, at least a portionof each jaw extending from a first end of the core member generally insaid forward direction when the jaws are closed, the respectiveextending portions each having a respective gripping surface; and asleeve member arranged to be moveable substantially parallel with thelongitudinal axis relative to the core member, the sleeve member havingat least one forward facing jaw-engaging surface, the jaws, when open,each presenting a respective reverse facing engaging surface to the atleast one jaw-engaging surface of the sleeve member; the sleeve memberbeing progressively moveable in the said forward direction to urge theat least one jaw-engaging surface of the sleeve member against thereverse facing engaging surfaces of the jaws, constraint of the jaws insaid forward direction causing urging of the sleeve member against thejaws to force the jaws to close; the hand tool further comprising twolever pins arranged to extend generally transverse to the longitudinalaxis and coaxially from opposite sides of the hand tool at least whenthe jaws are closed, each lever pin extending from and being integralwith a respective one of the jaws.
 2. A hand tool in accordance withclaim 1, wherein the core member is generally cylindrical and comprisesan external screw thread, and the sleeve member comprises acorrespondingly threaded bore extending along the longitudinal arm andarranged to receive and threadably engage the core member such thatmovement of the sleeve member along the longitudinal axis relative tothe core member is effected by rotation of the sleeve member withrespect to the core member about the longitudinal axis.
 3. A hand toolin accordance with claim 2, wherein the screw thread is left-handed. 4.A hand tool in accordance with claim 1, wherein the sleeve member isgenerally cylindrical.
 5. A hand tool in accordance with claim 1,wherein an outer surface of the sleeve member is adapted to be engagedby a spanner or socket for applying torque to the sleeve member aboutthe longitudinal axis.
 6. A hand tool in accordance with claim 1,wherein the sleeve member comprises a handle portion adapted tofacilitate gripping and rotation of the sleeve member by hand.
 7. A handtool in accordance with claim 1, wherein a second end of the core memberis arranged to extend through the sleeve member in the reverse directionbeyond a first end of the sleeve member when the sleeve member is incontact with the jaws.
 8. A hand tool in accordance with claim 7,wherein the second end of the core member is adapted to be engaged by aspanner or socket.
 9. A hand tool in accordance with claim 7, whereinthe second end of the core member is further adapted to receive and beengaged by a socket drive.
 10. A hand tool in accordance with claim 1,wherein the jaws, when forced closed by the sleeve member, are eacharranged to extend beyond a second end of the sleeve member in theforward direction.
 11. A hand tool in accordance with claim 1, havingtwo jaws.
 12. A hand tool in accordance with claim 1, wherein thegripping surfaces of the jaws are arranged to close generally radiallyand symmetrically on the longitudinal axis when the jaws are forced toclose by the sleeve member.
 13. A hand tool in accordance with claim 1,wherein each gripping surface includes a respective flat portionarranged to oppose a corresponding flat portion of at least one other ofthe at least two jaws.
 14. A hand tool in accordance with claim 1,wherein each gripping surface comprises respective teeth arranged tointermesh with corresponding teeth at least one other of the at leasttwo jaws.
 15. A hand tool in accordance with claim 1, wherein eachgripping surface comprises respective teeth arranged to oppose but notintermesh with corresponding teeth on at least one other of the at leasttwo jaws.
 16. A hand tool in accordance with claim 1, wherein eachgripping surface includes a respective generally V-shaped groovearranged to extend generally along the longitudinal axis to facilitatinggripping of generally cylindrical objects.
 17. A hand tool in accordancewith claim 1, wherein the at least one forward facing jaw-engagingsurface is inclined to face the longitudinal axis.
 18. A hand tool inaccordance with claim 1, wherein the forward facing jaw-engaging surfaceis generally frustoconical and radially disposed symmetrically about thelongitudinal axis.
 19. A hand tool in accordance with claim 1, whereinthe jaws are pivotally coupled to the core member.
 20. A hand tool inaccordance with claim 19, wherein each jaw comprises a respective pivotpin extending from a side of the jaw, each pivot pin being received in acorresponding respective slot in the core member, each said slotextending in a plane substantially perpendicular to the longitudinalaxis, the jaws and core member being adapted to permit rotation of eachjaw about its respective pivot pin in a plane substantially parallel tothe longitudinal axis and to permit movement of each pivot pin, in itsrespective slot, transverse to the longitudinal axis.
 21. A hand tool inaccordance with claim 20, wherein each jaw comprises two said respectivepivot pins, the two pivot pins of each jaw extending coaxially fromopposing sides of the jaw, the core member comprising at least onefurther slot, the at least one further slot extending in a planeparallel to the longitudinal axis, the at least one further slot beingarranged to accommodate a portion of a respective associated one of saidjaws to permit rotation of the associated one of said jaws about itspivot pins.
 22. A hand tool in accordance with claim 20 having two jaws,the respective slots, pivot pins, jaws and core member being arranged topermit parallel separation of the gripping surfaces.
 23. A hand tool inaccordance with claim 20, wherein the pivot pins are constrained intheir respective slots by the sleeve member when the jaws are closed.24. A hand tool in accordance with claim 23, wherein the sleeve ismovable in the reverse direction to release the pivot pin from theirrespective slots to enable decoupling of the jaws from the core.
 25. Ahand tool in accordance with claim 1, wherein, for each jaw, therespective reverse facing engaging surface is generally inclined at anangle to the respective gripping surface, the angle of inclination beinggenerally the same as that between the jaw-engaging surface or surfacesof the sleeve member and the longitudinal axis.
 26. A hand tool inaccordance with claim 1, wherein the jaws are arranged to present saidrespective reverse facing engaging surfaces to the or each jaw-engagingsurface of the sleeve member when the jaws are closed.
 27. A hand toolin accordance with claim 1, in combination with a lever assembly, thelever assembly comprising a lever having a first end adapted to engagethe lever pins of the hand tool, a second end providing a handle, and atleast one fulcrum pin extending transversely from a region of the leverbetween the first and second ends, a plate member for positioningagainst a surface from which an object is to be extracted, and a fulcrumpin support member extending in a direction generally perpendicular tothe plate member and providing a support for the fulcrum pin.
 28. Acombination in accordance with claim 27, wherein the fulcrum pin supportis adapted to provide an adjustable height support for the fulcrum pin.